Spin to charge conversion at Rashba-split SrTiO$_3$ interfaces from resonant tunneling

TL;DR

This paper presents a theoretical study of spin-charge interconversion at SrTiO$_3$ interfaces, demonstrating how resonant tunneling induces transverse charge currents consistent with experimental observations.

Contribution

It introduces a 6-band $oldsymbol{k.p}$ model combined with spin-resolved scattering theory to explain spin-charge conversion in STO Rashba interfaces, highlighting the role of resonant tunneling.

Findings

Transverse charge current depends on gate voltage.

Resonant tunneling explains asymmetric electronic transmission.

Theoretical results agree with experimental data.

Abstract

Spin-charge interconversion is a very active direction in spintronics. Yet, the complex behaviour of some of the most promising systems such as SrTiO$_3$ (STO) interfaces is not fully understood. Here, on the basis of a 6-band $\boldsymbol{k.p}$ method combined with spin-resolved scattering theory, we give a theoretical demonstration of transverse spin-charge interconversion physics in STO Rashba interfaces. Calculations involve injection of spin current from a ferromagnetic contact by resonant tunneling into the native Rashba-split resonant levels of the STO triangular quantum well. We compute an asymmetric tunneling electronic transmission yielding a transverse charge current flowing in plane, with a dependence with gate voltage in a very good agreement with existing experimental data.